This method determines the acidic constituents
in a lubricating oil to show relative changes occurring in an oil in oxidizing
conditions. The rising Total Acid Number is usually indicative
ofadvancing oxidation which leads to oil deterioration
and chemical changes in the oil molecule.

TAN expressed in milligrams of Potassium Hydroxide (KOH)
required to neutralize on weight (gram) of lubricant.

TAN
test kit is excellent in measuring the chemical changes in lubricants
which are caused by oil oxidation. The higher TAN result shows, the rising
in oil oxidation occurs in lubricants.